This invention relates to an assembly structure for a high frequency circuit apparatus. More specifically, the present invention relates to an assembly structure suitable for use in assembling a high frequency circuit apparatus such as a UHF circuit apparatus.
A high frequency apparatus such as a converter for converting a wave of a UHF band to a VHF band, for example, consists of a plurality of high frequency circuit blocks. The high frequency apparatus generally has a box-like metallic casing, which is divided by shield plates into a plurality of compartments corresponding to the high frequency circuit blocks. The high frequency apparatus is assembled by the steps of first fitting the high frequency circuit blocks, each consisting of high frequency circuit components such as resistors, transistors and the like wired in a predetermined arrangement, into the corresponding compartments, then connecting electrically the circuit blocks by terminals extending through the shield plates or connecting them electrically with external apparatus by terminals extending through an external frame of the shield case. Finally, a metallic cover is fitted to the shield case. Incidentally, inductance coils are often soldered directly to terminals disposed inside the compartments without using a circuit board in order to prevent the drop of Q. On the other hand, a circuit board for other components may be fitted to the shield case by soldering it to the terminals penetrating through the external frame of the shield case or through the shield plate, or to the terminals implanted in the bottom plate of the shield case. Still, alternatively, the circuit board may be directly screwed to the shield case.
In accordance with the conventional assembly structure of the high frequency apparatus such as the converter or the like described above, the terminals and the screw portions must be disposed inside the shield case in order to fix the circuit board and the coils in position, the result being a complicated construction and an increase in the number of components to be assembled. Moreover, the assembly work is extremely troublesome and complicated because the assembly of the circuit board and coils and connections between circuit boards must be carried out inside the compartments of the shield case. Still another drawback is that the adjustment of each high frequency circuit component is not easy. Among other drawbacks, the helical coil can be fitted only manually but can not be fitted automatically in place because of its shape. Furthermore, since the shield between the high frequency circuit blocks is made only by one shield plate, that is, since the apparatus has a single shield structure, the shield effect is not sufficiently high, especially for the helical resonator for which high stability operation is a requisite.